Analog Devices LINEAR LT8491 Manual page 78

LT8491
APPLICATIONS INFORMATION
Choose R = 5.76k which is the closest standard
DACI2
value.
=
R
FBIN2
⎛
1
⎝ ⎜
100k –R
FBIN1
=
1
⎛
⎝ ⎜
100k – 97,865
= 3404Ω
Choose R = 3.4k which is the closest standard
FBIN2
value.
R = 0.2 • R
DACI1 DACI2
= 0.2 • 5726Ω
= 1145Ω
Choose R = 1.1k which is the closest standard
DAC1
value.
1
C =
DACI
1000 •R
DACI1
1
=
1000 •1,145
= 873nF
• Like the output feedback resistors, the final input feed-
back resistors were chosen to be standard values using
an iterative process. The V
HW Config: Input Voltage Sensing and Modulation net-
work section were used to validate the selections:
R = 93.1kΩ
FBIN1
R = 3.24kΩ
FBIN2
R = 1.05kΩ
DACI1
R = 5.49kΩ
DACI2
C = 1µF
DACI
where:
V = 6V
X1
V = 53V
X2
78
1
Ω
⎞ ⎛ ⎞
1
–
⎠ ⎟
⎝ ⎜ ⎠ ⎟
R
DACI2
1
Ω
1
⎞
⎛ ⎞
–
⎝ ⎜ ⎠ ⎟
⎠ ⎟
5726
Ω
F
F
and V equations in the
X1 X2
For more information
• The 10A maximum charge current limit and 2.5A trickle
charge current limit are set by choosing R
R and R using the following formulas:
IMON_OUT IOW
0.0497
R =
SENSE2
I
( )
OUT MAX
R =
IMON_OUT
I
(
OUT MAXS0
1208
=
2.5 • 5m
= 96.64kΩ
where the nearest standard value is 97.6kΩ
24.3k •R
IMON_OUT
=
R
IOW
R – 24.3k
IMON_OUT
24.3k • 47.6k
=
97.6k – 24.3k
= 32,356Ω
where the nearest standard value is 32.4kΩ
• The input current limit is set by properly choosing
R . In this example, the panel can deliver up to
SENSE1
5.4A. Choosing a margin of 30% yields...
0.0505
= =
R
SENSE1
I
( )
IN MAX
• For greater charging voltage accuracy, it is recom-
mended that 0.1% tolerance resistors be used for the
output feedback resistor network.
• Please reference the LT8705 data sheet for completing
the remaining power portions of the LT8491.
www.analog.com
SENSE2
0.0497
Ω = ≅ 5mΩ
10
1208
Ω
•R
)
SENSE2
Ω
Ω
Ω
0.0505
= 7.2MΩ
1.3 • 5.4
,
Rev. 0